An audio/video information system for recording and playing back audio/video information has been described in U.S. Pat. Nos. 3,842,194 and 3,842,217 to Clemens herein incorporated by reference. According to this system, audio/video information is recorded in the form of geometric variations in spiral grooves on the surface of the disc. Disc replicas are then made of an insulating material such as vinyl and are coated first with a conductive material and then with a dielectric film. A metallized stylus is utilized as a second electrode forming a capacitor with a video disc. The audio/video information is monitored by the stylus which notes changes in capacitance between the stylus and the video disc as the geometric variations in the form of depressions pass under the stylus. The groove density of video discs is generally from about 1,000 to about 10,000 grooves per inch (400-4000 grooves per centimeter).
In U.S. Pat. No. 3,843,399 to Kaplan et al., a polymeric dielectric coating for the video disc is described wherein the polymeric dielectric coating is formed from styrene deposited in a glow discharge. While this dielectric coating is operative, it has been desired to have a dielectric coating with improved wear, age deterioration resistance, and adhesion to the conductive layer. In U.S. Pat. No. 3,982,066 to Nyman et al. and in U.S. Pat. Nos. 3,984,907 and 4,004,080 to Vossen, Jr. et al., herein incorporated by reference, the adhesion of polymeric dielectric layers to a conductive layer is improved by utilizing copper in the conductive layer at the dielectric interface. The copper is either employed as a separate layer interposed between a nickel/chromium/iron alloy layer and the polymeric layer, or the copper is used to form a pseudo alloy with the nickel/chromium/iron alloy. While the copper improves adhesion, it is subject to corrosion which causes instability in the polymeric dielectric layer and aggravates the deterioration of the dielectric layer. It has thus been desired to improve the adhesion between a polymeric dielectric layer and a conductive metal layer which does not employ copper at the dielectric interface.